Walnut oil is a good source of omega-3 fatty acids and other nutrients. For centuries herbalists have used the pointy green walnut leaves due to the high concentrations (up to 10%) of astringent compounds called tannins. Tannins tighten and constrict tissues, making them valuable for protecting areas of skin and controlling inflammation and itching. For more information on different nuts.

Properties and health benefit
Walnuts are the best for heart health, according to  Joe Vinson, PhD, a researcher at the University of Scranton in Pennsylvania. Joe Vinson, PhD says its because they have more antioxidants -- and better-quality antioxidants -- than other popular nuts. It is well known that walnut oil has omega 3 fatty acids, and it seems strange that walnuts appear to contain very small amounts of melatonin.

Walnut fatty acids raise omega 3 blood levels
Levels of the n-3 fatty acid eicosapentaenoic acid in addition to those of alpha linolenic acid are significantly raised in blood lipids by the intake of four walnuts a day in humans.
Nutr Metab Cardiovasc Dis. 2006; Department of Pharmacological Sciences, University of Milan, Milan, Italy.
Ingestion of alpha linolenic acid (ALA), with the richest source among dry fruits such as walnuts, is associated with cardiovascular prevention. The aim of this study was to selectively evaluate the effects of moderate walnut consumption on the levels of ALA and its metabolic derivatives in human blood. After a 2-week run-in period, 10 volunteers consumed 4 walnuts per day (in addition to their habitual diet) for 3 weeks. Fatty acid profiles, with special attention to levels of ALA and long chain polyunsaturated fatty acids were assessed in blood drops collected from fingertips. The data indicate that the administration of a few walnuts a day for 3 weeks significantly increases blood levels, not only of ALA, but also of its longer chain derivative eicosapentaenoic acids (EPA) with levels remaining elevated over basal values after washout. The findings of this pilot study indicate that plant ALA in appropriate food items favourably affects the n-3 LC-PUFA status.

Cognitive benefits, brain enhancement
Could a few walnuts a day help keep mentally sharp as you age? That's a possibility, according to a Tufts University study, although the study involved rats and has yet to be confirmed in humans. Weight-matched, aged rats were assigned to receive special chow mixes containing from zero to 9% walnuts. After eight weeks, the rats on the 2% and 6% walnut diets showed improvements in age-sensitive tests of motor and cognitive skills. In a human, the 6% walnut diet would be about the equivalent of eating an ounce of walnuts, seven to nine nuts, daily. The essential fatty acids and polyphenols and other antioxidants in walnuts might benefit neural tissue. But more is not better: The rats on the 9% walnut diet actually did worse on tests of "reference" memory.
   Comments: It is best to have a moderate intake of nuts and to include a wide variety in the diet.

Animal studies
Breast cancer
Dr. Elaine Hardman of Marshall University School of Medicine in Huntington, West Virginia fed genetically altered mice a diet containing what they estimated was the human equivalent of two ounces of walnuts per day. A separate group of mice were fed another diet without walnuts. Walnut consumption significantly decreased the number of mice with at least one tumor, the number of glands containing a tumor and the size of the tumors. The walnut-rich diet boosted omega-3 fatty acid concentrations, which contributed to the decline in tumor occurrence, but other components of the walnut contributed as well. April 2009.

J Nutrition, 2014. Walnuts Have Potential for Cancer Prevention and Treatment in Mice. Researchers have identified biochemicals, including n-3 (ω-3) fatty acids, tocopherols, β-sitosterol, and pedunculagin, that are found in walnuts and that have cancer-prevention properties. Mouse studies in which walnuts were added to the diet have shown the following compared with the control diet: 1) the walnut-containing diet inhibited the growth rate of human breast cancers implanted in nude mice by ∼80%; 2) the walnut-containing diet reduced the number of mammary gland tumors by ∼60% in a transgenic mouse model; 3) the reduction in mammary gland tumors was greater with whole walnuts than with a diet containing the same amount of n-3 fatty acids, supporting the idea that multiple components in walnuts additively or synergistically contribute to cancer suppression; and 4) walnuts slowed the growth of prostate, colon, and renal cancers by antiproliferative and antiangiogenic mechanisms. Cell studies have aided in the identification of the active components in walnuts and of their mechanisms of action. This review summarizes these studies and presents the notion that walnuts may be included as a cancer-preventive choice in a healthy diet.

Walnut Research
Melatonin in walnuts: influence on levels of melatonin and total antioxidant capacity of blood.
Nutrition. 2005. Reiter RJ, Manchester LC, Tan DX. Department of Cellular and Structural Biology, The University of Texas Health Science Center, San Antonio, Texas
We investigated whether melatonin is present in walnuts (Juglans regia L.) and, if so, tested whether eating walnuts influences melatonin levels and the total antioxidant status of the blood. Melatonin was extracted from walnuts and quantified by high-performance liquid chromatography. After feeding walnuts to rats, serum melatonin concentrations were measured using a radioimmunoassay and the "total antioxidant power" of the serum was estimated by using the trolox equivalent antioxidant capacity and ferric-reducing ability of serum methods. Conclusion: Melatonin is present in walnuts and, when eaten, increase blood melatonin concentrations. The increase in blood melatonin levels correlates with an increased antioxidative capacity of this fluid.

Walnut derived sex pill?
Kim Kah Hwi, a Malaysian scientist, headed a team of researchers from the the University of Malaya to develop "N-Hanz", tablets which contain walnut extract and have shown positive results on 40 volunteers against erectile dysfunction. "It takes about an hour for the effects to set in and it will last for about four hours," said Kim Kah Hwi. Kim said the active ingredient was an amino acid called arginine, which is absorbed into the body and converted into nitric oxide.
   Comments: If this N-Hanz walnut extract works, it is not likely due to arginine, but something else since it would take massive doses of arginine to have any effect on erectile function.

Emails
Q. Are Freeze Dried Green Black Walnut Hulls effective for parasites? Are there any health issues or side effects from
Freeze Dried Green Black Walnut Hulls? Dr. Hulda Clark said it killed all 100 parasites she tested it for. The question is are there also side effects?
   A. We have not studied freeze dried green black walnut hulls enough to make a definitive statement. We don't consider Dr. Hulda Clark to be a reliable source when it comes to nutritional medicine.

Can walnuts cause acne pimple eruptions?
    Some people may be sensitive to nuts and break out with acne pimples when they eat walnuts or other nuts.